A conventional electrochemical cell packaging material is disclosed in Patent Document 1 listed below. This packaging material is a laminated material composed of a base material layer as the outermost layer, a barrier layer, and a thermally adhesive layer as the innermost layer which are laminated successively. Putting the thermally adhesive layer against another and heat-sealing them together around the periphery produces a packaging member for an electrochemical cell. The packaging member encloses a space for housing cell elements, such as electrolyte liquid and separators, and the housing space is formed by press-forming the packaging material cut in a rectangular shape.
In recent years, electronic devices that incorporate electrochemical cells have been made increasingly compact and slim, and to allow electrochemical cells to be housed in narrow spaces, packaging members for electrochemical cells need to be formed in thin, sharp shapes. To achieve that, according to Patent Document 1, an oriented nylon film is used as the base material layer for its excellent formability.